tbuckley/cabot-search huggingface dataset:
Abstract P3063: Downregulation Of The T Cell Unfolded Protein Response Precedes T Cell Cardiac Infiltration In Experimental Heart Failure With Preserved Ejection Fraction
Authors: Sasha Smolgovsky, Abraham Bayer, Francisco J Carrillo-Salinas, Kuljeet kaur, Mark Aronovitz, Erin Sanders, Brandon Theall, Robert M Blanton, Pilar Alcaide
Journal: Circulation Research (2022)

Introduction: Diastolic dysfunction in Heart Failure with Preserved Ejection Fraction (HFpEF) is associated with T cell systemic inflammation and downregulation of myocardial unfolded protein response (UPR) genes. The T cell UPR can modulate T cell effector function and immune responses, yet this is largely unexplored in HFpEF. Hypothesis: We hypothesized T cells contribute to cardiometabolic HFpEF and that metabolic and nitrosative stress-induced alterations of the T cell UPR modulate T cell activation and diastolic function. Methods: Male C57/BL6 (wild-type, WT) or T cell receptor alpha-deficient ( Tcra-/-) were fed a high-fat diet (HFD) and L-NAME for 1, 3, and 5 weeks, or standard chow (STD). We assessed diastolic function by invasive hemodynamic analyses. Immune cells were characterized in the heart and spleen by flow cytometry, and cardiac pathology was assessed by histology. The UPR gene expression was evaluated in splenic CD4 + T cells over time by qPCR. Results: Unlike WT mice, Tcra-/- mice fed HFD/L-NAME for 5 weeks did not develop diastolic dysfunction or cardiomyocyte hypertrophy, demonstrating a critical role for T cells in experimental cardiometabolic HFpEF. Indeed, cardiac CD4 + T cells were increased in WT mice fed HFD/L-NAME for 5 weeks compared to STD, concordant with an expansion of splenic CD44 hi CD62l lo interferon-gamma (IFNγ) + effector cells. Strikingly, splenic T cells also experienced downregulation of the UPR proteins activating transcription factor 4 ( Atf4 ), Atf6 , and X box-binding protein 1 ( Xbp1s/u ). We found that the Atf4 arm of the T cell UPR is the earliest responder to HFD/L-NAME, with observed downregulation of Atf4 and its downstream effector C/EBP homologous protein ( Chop ) as early as 3 weeks, prior to onset of diastolic dysfunction, followed by the subsequent downregulation of Atf6 and Xbp1s/u . Conclusions: T cells contribute to diastolic dysfunction and cardiomyocyte hypertrophy in experimental cardiometabolic HFpEF. Early modulation of T cell Atf4 precedes diastolic dysfunction, enhanced IFNγ + effector T cell activation, and global T cell UPR downregulation. Ongoing studies are focused on understanding the functional consequences of impaired T cell UPR in cardiometabolic HFpEF.
Small cell lung cancer with paraneoplastic nephrotic syndrome
Authors: ES Boon, AA Vrij, C Nieuwhof, JA van Noord, E Zeppenfeldt
Journal: European Respiratory Journal (1994)

We present a case of nephrotic syndrome, associated with small cell lung carcinoma. Renal biopsy revealed membranous glomerulonephritis, probably due to immune complex deposition with tumour antigen. Complete remission of the small cell lung carcinoma after chemotherapy was followed by regression of the nephrotic syndrome. This regression persisted even when brain metastases developed, without simultaneous relapse of tumour outside the central nervous system.
Abstract P3088: The Histone Lysine Methyltransferase SMYD1a Protects Heart From Ischemic Injury By Regulating OPA1 Mediated Cristae Remodeling And Supercomplex Formation
Authors: Marta W Szulik, Steven Valdez, Maureen Walsh, Kathryn Davis, Ryan Bia, Emilee Horiuchi, Sean O'Very, Anil Laxman, Linda Nicolova, Hanin Sheikh, Samuel Hickenlooper, Mickey R Miller, Li Wang, June Garcia-Llano, Christopher Tracy, Stavros G Drakos, Katsuhiko Funai, Dipayan Chaudhuri, Sihem Boudina, Sarah Franklin
Journal: Circulation Research (2022)

The histone lysine methyltransferase SMYD1 has been shown to be critical for embryonic cardiac development and in maintaining cardiomyocyte homeostasis in adult mice. Subsequently, we reported that loss of Smyd1 in the adult mouse myocardium leads to progressive cardiac hypertrophy and heart failure, which is accompanied with downregulation of mitochondrial proteins involved in oxidative phosphorylation, including Ppargc1a , and reduction of mitochondrial respiration capacity. To build upon these results and evaluate if SMYD1a can attenuate disease-induced remodeling in an animal model, we generated transgenic mice which inducibly express SMYD1a (the human ortholog) in cardiomyocytes and subjected them to permanent occlusion (PO) of the LAD. This lead to &gt;50% reduction in infarct size and preserved cardiac function, as compared to littermate controls. Additionally, we demonstrated that under physiological conditions SMYD1a maintains metabolic homeostasis by regulating expression of Ppargc1a and its downstream targets, including components of the electron transport chain. Our molecular analysis shows that observed protection from ischemic injury results from enhanced mitochondrial respiration through Complex I and II as well as increased ATP production. This is associated with increased mitochondria cristae, and formation and stabilization of respiratory chain supercomplexes within the cristae. These changes in cristae structure occur concomitant with enhanced OPA1 expression, a major regulator of mitochondrial fusion and cristae morphology. Through this work we have established that OPA1 is a novel, functionally important downstream target of SMYD1a by which cardiomyocytes upregulate energy efficiency, protecting them from ischemic injury. These results also highlight SMYD1a as the only known epigenetic regulator of cristae morphology and provide broad implications for understanding the epigenetic mechanisms driving cardiac metabolism. Ultimately this work has identified a novel signaling pathway by which cardiomyocytes regulate energy efficiency, protecting them from ischemic injury.
Abstract P2044: The Cardioprotective Egr-1 And Maladaptive Sp-1 Zinc Finger Transcription Factor Reciprocally Regulates Expression Of The Cardiomyocyte Performance Enhancing Protein S100a1
Authors: Martin Busch, Thien-Kim Bui, Lukas Adrian, Fabian Guenther, Mandy Rettel, Frank Stein, Jan Haas, Hagen Klett, Melanie Boerries, Benjamin Meder, Christoph Dieterich, Hugo A Katus, Patrick Most
Journal: Circulation Research (2022)

Background and Hypothesis: Expression of the cardiomyocyte (CM) protein S100A1, which improves contractile performance of the heart, sharply increases during postnatal myocardial maturation but declines rapidly in failing hearts. We therefore hypothesized that CMs are wired with transcriptional factors (TFs) that positively and negatively regulate S100A1’s gene locus activity. Understanding these reciprocal circuits may be relevant for advanced therapeutic modulation of S100A1’s abundance in diseased hearts. Methods and Results: H9C2 rat cardiomyoblasts, an animal-free in vitro tool, displayed a strong concordant rise in S100A1 mRNA and protein levels (8.1+/-1.1 vs. cont.; n=9, p&lt;0.05) amongst other CM markers (i.e., SERCA2a) over a 5-day CM differentiation protocol. Overall TF activity during this process was computationally inferred from TF binding site (TFBS) assessments in promoters of all actively regulated transcripts provided by a time-resolved (undifferentiated, day 0, 2 and 5) transcriptome analysis. From these TFs, EGR1 and SP1 amongst eight others were chosen due to their abundance both in differentiated H9C2-CMs and adult rat hearts and TFBS in the -1000 to +500 bp rat S100A1 gene promoter region due to a 5’ RACE-PCR based transcription start site identification in our model. To capture the relevant TFs from this group, we next co-incubated nuclear extracts from H9C2-CMs with biotinylated fragments of the aforementioned S100A1 promoter region coupled to streptavidin beads. S100A1 promoter-bound TFs were identified by mass spectrometry and only factors with a &gt;2-fold enrichment over control were selected delivering EGR1 and SP1 as top hits. Subsequent siRNA-mediated silencing of both TFs yielded an EGR1 and SP1 knock-down dose-dependent inhibition (80%; p&lt;0.05 vs. contr., n=9) and amplification (126%; p&lt;0.05 vs. contr., n=9) of the rise both in S100A1 mRNA and protein levels in the H9C2-CM model that validated our comp./exp. pipeline and biological relevance of our TF hits, respectively. Conclusion: Our study identified the known cardioprotective EGR1 and maladaptive SP1 as novel positive and negative TF regulators of CM S100A1 expression and targets for therapeutic S100A1 gene locus modulation i.e., by SP1 TFBS gene-editing.
Abstract P2006: S100A1 And STRIT1 Redundantly Governs Responsiveness Of The Heart To Hemodynamic Stress Via Modulation Of SERCA2a Activity
Authors: Zegeye Hailu Jebessa, Andrea Schneider, Matthias Dewenter, Michael Berlin, Catherine A Makarewich, Eric N Olson, Marc Freichel, Martin Busch, Johannes Backs, Patrick Most
Journal: Circulation Research (2022)

Background &amp; Objectives: SR Ca2+ load, which is sustained by SERCA2a pump activity, is a critical determinant for cardiac performance regulation &amp; adaptation. Independent studies identified both S100A1 &amp; STRIT1 as molecular enhancers of SERCA2a activity in the heart. S100A1 &amp; STRIT1 decline in post-myocardial infarction hearts aggravated the transition to adverse cardiac remodelling &amp; contractile failure. We therefore hypothesized that S100A1 &amp; STRIT1 could act as independent but potentially redundant molecular switches for SERCA2a activity. Methods &amp; Results: S100a1 knock-out (SKO) mice display no overt cardiac contractile or structural abnormalities in the absence of stress. RNA-seq transcriptomic analysis of left ventricle (LV) of SKO &amp; wild type (WT) identified Strit1 amongst the top 3 most upregulated genes in SKO LV. We validated STRIT1 upregulation by RT-PCR as well as by immunoblotting (IB) that yielded a 15-fold increase compared with WT. Age lapse-resolved RT-PCR analysis showed Strit1 response to S100a1 knockout begins at post-partum day 5 &amp; reaches plateau in adulthood. Next, we generated Strit1-S100a1 double knock out mice (StSKO), which showed only a mild decline in cardiac contractile performance. Interestingly, LV tissue serin-16 phospholamban (PLN) phosphorylation levels &amp; PLNs pentameric state were found to be enhanced. WT, SKO &amp; StSKO mice were then subjected to transaortic constriction (TAC) &amp; followed for 60 days, which fully unmasked the mutually compensatory functions of S100A1 &amp; STRIT1. In TAC-StSKO hearts showed significantly higher decline in LV %EF, significantly increased LV end-systolic volume &amp; LV end-systolic diameter, &amp; significantly increased cardiac hypertrophic growth together with concordant molecular markers. TAC-SKO mice did not show any decline in STRIT1 protein upregulation, while TAC-WT hearts showed a putatively compensatory increase in the S100A1/STRIT1 protein ratio. Conclusion: Our first results indicates that STRIT1 &amp; S100A1 can act as compensatory molecular switches securing sufficient SERCA2a activity. As such, our study further sheds new light onto the novel concept of “molecular redundancy” to secure &amp; protect cardiac key effector activities to cope with distinct hemodynamic stressors
Abstract P2042: Down-regulation Of Microrna-16 Improved Selenium Deficiency-induced Cardiac Dysfunction In Rats Through Wnt/β-catenin Signaling
Authors: Yujie Xing, Zhongwei Liu, Ling Zhu, Xiqiang Wang
Journal: Circulation Research (2022)

Objective: To investigate the mechanisms and effects of down-regulation of microRNA-16 in selenium deficiency-induced cardiac dysfunction in rats. Methods: Selenium deficiency was induced by low selenium diet. Injection of AAV9-carried microRNA-16 interference was used to down-regulate microRNA-16. Cardiac functions were evaluated by echocardiography and serum BNP concentrations. The expression of microRNA-16 was examined by RT-PCR. Expression levels of wnt, β-catenin, c-myc and caspase-3 were evaluated by Western blotting. Results: Down-regulation of microRNA-16 in rats with selenium deficiency significantly improved cardiac functions. Meanwhile, the down-regulation of microRNA-16 reduced the expression of wnt1, β-catenin and TCF in the Wnt/β-catenin signaling pathway, and the expression of c-myc and caspase-3 were also decreased. Conclusions: The down-regulation of microRNA-16 can improve the cardiac function of rats with selenium deficiency via the inactivation of Wnt/β-catenin signaling pathway.
Abstract P2019: Do Changes In Metabolism Or Lactation Mediate The Reversal Of Pregnancy-induced Cardiac Growth?
Authors: Emily B Schulman, Bradford G Hill, Helen E Collins
Journal: Circulation Research (2022)

During pregnancy, the maternal heart undergoes physiologic growth, which reverses following parturition and is associated with the restoration of hemodynamic parameters. However, the molecular processes underlying the reversal of pregnancy-induced cardiac growth and the time frame in which these changes occur remain unclear. Because changes in cardiac metabolism have been shown to influence the remodeling in the maternal heart, changes in metabolism may also contribute to the reversal of pregnancy-induced remodeling. Therefore, the goal of this study was to examine the underlying processes that contribute to the structural and functional changes occurring in the maternal heart following parturition. Timed pregnancy studies in 12-week-old female FVB/NJ mice showed that heart weight to tibia length (HW:TL) and cardiomyocyte size were highest in lactating 1-week post-birth (PB) mice versus mid-pregnant (8 d), late-pregnant (LP; 16 d), and non-pregnant (NP) mice. Interestingly, we also found that HW:TL was significantly reduced in non-lactating 1-week post-birth mice (PBNL) compared with LP mice. To determine the time-course of the reversal of pregnancy-induced remodeling and to examine the impact of lactation, we examined HW:TL in PB and PBNL mice 1, 3, and 6 weeks following parturition. We find that HW:TL is significantly higher in lactating PB mice versus non-lactating PBNL mice at 1 (8.71 ± 0.05 v 7.09 ± 0.26 mg/mm) and 3 weeks following parturition (8.90 ± 0.40 v 6.92 ± 0.56 mg/mm); however, 6 weeks after parturition, HW:TL was comparable between PB (7.35 ± 0.29 mg/mm) and PBNL groups (7.05 ± 0.18 mg/mm). Nevertheless, HW:TL remained elevated for 6 weeks after parturition in PB and PBNL mice compared with NP mice. RNA-Seq showed reductions in metabolic transcripts in PB hearts, including Pdk4 . Immunoblot analysis of key metabolic proteins showed that Pdk4 was reduced in hearts from 1 and 3 PB versus 1 and 3 weeks PBNL and NP. Together, these findings suggest that lactation influences the reversal of pregnancy-induced cardiac growth, which may be due in part to changes in cardiac metabolism.
Abstract P1104: Lower Troponin Expression In The Right Ventricle Of Rats Explains Interventricular Differences In E-c Coupling
Authors: Young Keul Jeon, Jae Won Kwon, Sung Joon Kim
Journal: Circulation Research (2022)

Despite distinctive functional and anatomical differences, a precise understanding of the cardiac interventricular differences in excitation-contraction (E-C) coupling mechanisms is still lacking. Here, we directly compared rat right and left cardiomyocytes (RVCM and LVCM). Whole-cell patch clamp, IonOptix system and fura-2 fluorimetry were used to measure electrical properties (action potential and ionic currents), single cell contractility and cytosolic Ca 2+ ([Ca 2+ ] i ), respectively. Myofilament proteins were analyzed by immunoblotting. RVCMs showed significantly shorter action potential duration (APD) and higher density of transient outward K + current ( I to ). However, the triggered [Ca 2+ ] i change (Ca 2+ transient) was not different, while the decay rate of the Ca 2+ transient was slower in RVCM. Although the relaxation speed was also slower, the sarcomere shortening amplitude (ΔSL) was smaller in RVCM. SERCA activity was approximately 60% lower in RVCM, partly responsible for the slower decay of the Ca 2+ transient. Immunoblot analysis revealed lower expression of the cardiac troponin complex (cTn) in RVCM, implying a smaller Ca 2+ buffering capacity ( κ S ), which was proved by in situ analysis. The introduction of these new levels of cTn, I to and SERCA into a mathematical model of rat LVCM reproduced the similar Ca 2+ transient, slower Ca 2+ decay, shorter APD and smaller ΔSL of RVCM. Taken together, we show reduced expression of cTn proteins in the RVCMs, which provides an explanation for the inter-ventricular difference in the E-C coupling kinetics.
Abstract OEC102: Unbiased Discovery Of Allograft Inflammatory Factor 1 As A New And Critical Immunometabolic Regulatory Node During Cardiac Injury
Authors: Matthew DeBerge, Edward B Thorp
Journal: Circulation Research (2022)

Introduction: Myocardial infarction (MI) mobilizes macrophages, which are the central protagonists of tissue repair in the infarcted heart. While macrophages are necessary for repair after MI, they can also contribute to adverse remodeling and progression to heart failure. We sought to identify novel mediators of maladaptive macrophage responses by performing single cell RNA sequencing of a patient with ischemic cardiomyopathy. This led to the unbiased identification of Allograft inflammatory factor 1 ( AIF1 ) as the most significant differentially expressed gene in macrophages compared to other cardiac cells during human heart failure. Hypothesis: Since AIF1 was specifically expressed in macrophages during ischemic heart failure, we next tested the hypothesis that AIF1 promoted maladaptive macrophage responses after MI. Methods and Results: Using autopsy samples from human acute MI patients or a murine model of permanent occlusion MI, we found that AIF1 was increased in macrophages, but not neutrophils or monocytes, after MI. To test the functional significance of AIF1 expression in macrophages after MI, we generated bone marrow chimeric mice where Aif1 -deficiency was restricted to only cells of hematopoietic origin. Despite comparable levels of surgically induced injury, loss of Aif1 was associated with increased proreparative macrophages, smaller infarct sizes, and preservation of cardiac function compared to wild-type controls. Therapeutic targeting of Aif1 with anti-sense oligonucleotides also conferred cardioprotective responses after MI. Mechanistically, AIF1 promoted actin polymerization in bone marrow-derived macrophages after TLR4 stimulation leading to increased glycolytic metabolism and inflammatory IL-6 and TNF-α production. AIF1 also suppressed calcium uptake in the mitochondria to limit mitochondrial metabolism and anti-inflammatory IL-10 production. Conclusion: These data newly reveal a proinflammatory role for AIF1 in the infarcted heart through inflammatory glycolytic reprogramming of macrophages, which required both calcium mobilization and actin polymerization. Targeted knockdown of AIF1 led to cardioprotection supporting further exploration of macrophage AIF1 as a therapeutic target after MI.
Abstract P3015: Cite-seq Identifies A Novel Role For Macrophage Trem2 In A Murine Model Of Hfpef
Authors: Charles Smart, Daniel Fehrenbach, Jean J Wassenaar, Vineet Agrawal, Anna R Hemnes, Amanda C Doran, Meena Madhur
Journal: Circulation Research (2022)

Deoxycorticosterone acetate (DOCA)-salt is a common model of hypertension and has been used to study heart failure with preserved ejection fraction (HFpEF) in rats. Our goal was to validate DOCA-salt as a mouse model of HFpEF and to identify immune mediators of cardiac remodeling using unbiased methods. DOCA-salt mice underwent uninephrectomy, implantation of a DOCA pellet, and supplementation of the drinking water with 1%NaCl for three weeks. Control mice underwent a sham procedure and received normal water. Compared to control mice, DOCA-salt mice exhibited increased systolic blood pressure, cardiac hypertrophy, and decreased time to exhaustion upon treadmill exercise testing. In addition, DOCA-salt mice exhibited albuminuria, indicative of renal glomerular injury. On echocardiography, DOCA-salt mice exhibited a preserved ejection fraction. Invasive hemodynamic studies revealed an increased tau constant (5.70±.24, 8.22±.45; n=8,5) in DOCA-salt mice, consistent with diastolic dysfunction. CITE-seq, a novel technique to obtain transcriptomic and surface marker expression on single cells, was performed on a total of 4,359 and 7,600 sorted leukocytes from four sham and four DOCA-salt left ventricles, respectively. Differential gene expression analysis revealed major transcriptional changes in cardiac macrophages between groups and identified Trem2 as being upregulated in cardiac macrophages. We validated a two-fold increase in Trem2 gene expression in left ventricles of DOCA-salt mice and observed a two-fold increase in cardiac Trem2+Mac2+ cells in DOCA-salt by immunofluorescence. To test whether Trem2 has a causal role in HFpEF, wild type and Trem2 deficient animals were subjected to DOCA-salt. After DOCA-salt, Trem2-deficient mice displayed significantly increased heart weight to tibia length ratios (9.39±0.20, 11.21±0.80; n=6-7) and albumin to creatinine ratios (5.5±1.2, 14.2±2.9; n=6-7) compared to wild-type controls. No difference in albuminuria was observed at baseline (0.36±0.05, 0.46±0.10; n=10). In conclusion, the DOCA-salt mouse model induces key features of HFpEF and identifies Trem2 as a potential novel modulator of cardiac remodeling and renal injury.
Abstract P3134: Mechanosensitive Piezo2 Channel Mediates The Exaggerated Exercise Pressor Reflex In A Mouse Model Of Hind Limb Ischemia.
Authors: qinglu li, Mary G Garry
Journal: Circulation Research (2022)

The exercise pressor reflex (EPR) is a reflexive mechanism in which blood pressure and heart rate increase in response to skeletal muscle contraction. These reflexive increases are caused by both mechanical and metabolic stimulation of group III and IV afferent neurons innervating in contracting skeletal muscle. Patients with peripheral artery disease (PAD) have an exaggerated EPR which contributes to exercise intolerance and morbidity and mortality. Recently, we developed a mouse model of EPR, and have validated that the mouse model is similar to our rat model. With this mouse model of EPR, we studied the EPR following femoral artery ligation (FAL), briefly the right hind limb common femoral artery was ligated and transected between the proximal end near the groin and the distal end near the bifurcation of the popliteal artery and the saphenous artery. The same procedure was done without femoral artery ligation and transection for sham control. We observed that the mean arterial pressure (MAP) responses to ventral root stimulation (which excite metabo- and mechano-sensitive afferent neurons) and passive stretch (mechanosensitive stimulation only) were exaggerated 72 hours following FA ligation when compared to sham treated controls. The exaggerated EPR was significantly reduced by intra-arterial administration of Gadolinium (a mechanical sensitive group III afferent neurons inhibitor), GsMTx-4 (a selective Piezo2 inhibitor), but not by SB-705498 (a TRPv1 receptor inhibitor). Additionally, selective stimulation of metabolically sensitive afferent neurons by intra-arterial capsaicin injection (an activator of metabolically sensitive afferent neurons) induced equal, dose-related increases in MAP in both FA ligation and control mice. Finally, immunofluorescence staining visualized that the mechano-sensitive channel Piezo2 is localized in most large diameter neuron cells in mouse lumbar DRG. First, these results indicate that metabolically sensitive afferent neurons are not affected by FAL. Second, we observed that the exaggerated EPR in a murine model of PAD is mediated by mechanically sensitive group III neurons, which is due, in part, to Piezo2 receptor activation. Future studies will be aimed at interrogation of the mechanosensitive mechanisms that mediate this abnormal response to exercise in a model of PAD. The goal of these studies will be to determine molecular targets through which the exaggerated EPR can be normalized to allow for the prescription of exercise in PAD patients.